Feeding mechanism for sewing machines



R. A. NERIN'G FEEDING MECHANISM FOR SEWING MACHINES March 25, 1958 5 Sheets-Sheet 1 Filed June 20, 1956 INVENTOR. I fioberz A. Ale/mg W ATTORN)! I March 25, 1958 R. A. NERING 2,327,869

FEEDING MECHANISM FOR SEWING MACHINES Filed June 20, 1956 I 5 Sheets-Sheet 2 INVENTOR. 56 A. Nerf/1g A TTORNE'Y March 1958 R. A. NERING 2,827,869

' FEEDING MECHANISM FOR SEWING MACHiNES Filed June 20, 1956 7 5 Sheets$heet 5 INVENTOR. Roberf A. Nerf/2g BY Maw .4 TTORNEY March 25, 1958 R. A. NERING 2,827,869

FEEDING MECHANISM FOR SEWING MACHINES Filed June 20, 1956 '5 Sheets-Sheet 4 INVENTOR. Robert A. Nari/7g ATTORNEY f March 25, 1958 I R. A. NYERING FEEDING MECHANISM FOR SEWING MACHINES 5 Sheets-Sheet 5 Filed June 20, 1956 INVENTOR. Robe/'2 14. )Verz'ng I ATTORNEY FEEDING MECHANISM FOR SEWING. MACHINES Robert A. Nering, Yonkers, N. Y., assignorto Merrow Sales Corp, New York, N. Y., a corporation of New York Application June 26, 1956, Serial No. 592,654

9 Claims. or. 112-207 This invention relates .to improvements in feeding mechanisms for sewing machines.

The most common form of feedingmechanism found in domestic and industrial sewing machines comprises a lower feed gripper mounted below an apertured needle plate complemented by apresser foot above andv opposite the lower feed gripper. Material to be sewed is gripped between the presser foot and the lower feed gripper which performs a complex oscillatory motion during which the gripper is raised above the surface of the. needle. plate whereafter it travels parallel .tothe needle .plate, most commonly in a direction away from the operator. The presser foot bears down on the material Iwith.spring force and-is. smooth on its under side, whereasthe lowerfeed gripper has a serrated upper surface fortsecurely engage ing the material to be transported.

Difficulties are encountered with the conventional feeding'mechanism if layers of smooth and. slippery material are to be sewed.

Materials consisting in part or entirely of synthetic yarns generally have a smooth surface and relatively little friction exists between several superimposed layers. If such materials are fed by a conventional feeder of the aforementioned general type, the bottommost layer. is fed positively "by the lower feed gripper, whereas the frictional engagement between the presser foot. and. the top most layer tends to retard it. By reason-of the low degree of friction between the several layers, the layers tend to slide relatively to one another, resulting in work of substandard quality.

Similar difliculties are encountered when, relatively thick-layers of conventional material are to be .sewed or if the top layer is of -a character which encounters considerable frictional resistance by the presser foot. This,

is the case, for example, if the top layer is a sheet of plastic or oiled material.

The aforementioned difliculties maybe overcome by use of a feeding mechanism which'positivelyand equally grips the top and bottom layer and imparts to both layers the same feeding motion.

Feeding devices of the latter type are known in principle. For example, sewing machines are .inuse which are equipped with a so-called uppertwalking or oscillating presser foot in addition to the conventional presserfoot and the conventional lower feed gripper. In the known machine the walking or oscillating. presser foot is operated by a separate drivemechanism and two drive shafts are provided, one for. operating thelower feed gripper and a second shaft for operatingthe upperfeed gripper or oscillating presser foot. The known form of construction is relatively complex and requiresuseparate adjustments for the top and bottom feeders. Such. adjustments usually involve a resetting or exchange of cams.

In domestic sewing machines adjustable cam: means are preferred, whereasintcommercialmachines it. is preferredto exchange cams of difierent eccentricity, so as. to make it difficult, if not impossible;fomtheoperator'to it ice 2 1 select a faster feed. and a lower number of stitches per inchlthan specified.

The invention provides a feeding mechanism in which no separate drive shaft for the upper feed gripper is required and in which an adjustment of the horizontal stroke of the lower feed gripper automatically results in the upper gripper from the mechanism already provided in the machine for actuating the lower feed gripper.

The invention, and particularly the attachment, may advantageously be applied to machines equipped with a lower differential feed mechanism comprising two lower feed grippers traveling horizontal strokes of different magnitude for thepurpose of gathering of material for shirring or for the production of ruflles.

The objects, features and advantages of this invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration, an embodiment of the invention in the form of an adapter for converting a machine originally constmcted with one lower feed gripper and one upper presser foot into a machine having one upper and one lower feed gripper in addition to-the presser foot. The invention also resides in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of the invention which are believed to be novel will be particularly pointed out in the claims appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of it in which:

Figure l is a perspective View of the gripper end of a conventional sewing machine converted by the invention into a double-gripper machine; and

Figures 2 to 6 are perspective views of the machine of Figure 1 in successive stages of disassembly to show its construction andimportant structural details.

In the following description and in the claims various details will be identified by specific names for convenience; The names, however, are intended to be generic in their application. Corresponding reference characters refer to corresponding parts in the several figures of the drawings.

The drawings accompanying, and forming part of, this specification disclose specific details of the invention for the purpose of explanation of broader aspects, but it is understood that the details may be modified in various respects without departure from the principles of the invention and that the invention may be applied to other structures than the one shown.

Referring to Figures 1 and 6, the machine comprises ashousing 11 through which a main drive shaft 12 ex tends. The;drive shaftcarries a hand wheel 13 which also has a V-groove for engagement by a round or V-belt for driving the machine from a power shaft and clutch generally arranged below the table or bench on which the machine is mounted. The V-groove of the hand wheel :is not visible in the drawings because it is obscured by the far end of the housing.

An upper geared shaft 14 extends through the housing andrevolves in a direction opposite to the direction of rotation of the-shaft 12 by reason of a spur gear drive,

Patented Mar. 25, 1958 in the interior of the housing 11. A needle carrier is pivotally mounted at 16 and is oscillated about the pivot axis 16 by a connecting rod obscuredby the needle carrier 15 and extending from a crank 17 on-the upper;

geared shaft 14 to a. pin or pivot 18 on the needle carrier. The needle 1'9'is curved and is clamped to the needle carrier at 20. 7 most position. At the other end of its stroke the needle extends through an apertured needle plate 21 .(see also Figure l). The needle plate 21 lies in substantially the same plane as a table plate 22 and has a plurality of apertures including a slot 23 through which the needle extends. Other apertures, and slots of the needle plate will be described later. 7 I V The machine is fitted with a trimming device for trimming the material fed into the machine immediately adjacent the seam to be sewed. This tirmming device lies adjacent the needle plate and is best seen in Figures 5 and 6 showing the machine with the needle plate removed. The device comprises a lower, stationary cutting knife 24 past which an upper movable blade or knife 25 moves. The upper knife is clamped to an arm 26 by means of a bracket 27 and a screw 28. The arm protrudes from a slot 29 in the housing and is moved up and down by a cam mechanism (not visible) on the upper shaft 14. Since the shafts 12 and 14 are geared at the ratio one-to-one, the trimming device 24,25 performs a cutting motion for each stitch, and correspondingly for each advance of the material by the feeder.

A hinged cover 39 (Figure 1) conceals a cam mechanism which is exposed to view in Figure 2 showing the cover 3% removed. In Figure 2 the table plate 22 is also removed to show details of the feeding mechanism, which will now be described.

The feeding mechanism comprises a lower feed gripper 31 (see also Figure 6) mounted on a'feed carrier 32 by a screw 33. The feed carrier 32 has two forked horizontal guideways' 34 and 35 extending in opposite directions, each guideway fitting a rectangular block or crosshead 36 and 37, respectively. A pin 38 extends through the block 36 and is seated in a horizontal bore running substantially parallel to the drive shaft and visible in Figures 2 and 3 at 39. The pin 38 is thus fixed and furnishes a pivotal support for the left end of the feed carrier 32 which may pivot about the pin and slide in a horizontal direction relatively to the pin to the right and to the left as is readily seen in Figure 6. g

The block 37 fits on an eccentric portion 40 of the drive shaft 12 which imparts an oscillating motion to the right end of the feed carrier in a substantially vertical direction. This is the motion which causes the lower feed gripper 31 to protrude above the needle plateas shown in Figure 1 and to be retracted slightly below the surface of the needle plate as shown in Figure 3 where the teeth of the lower feed gripper are not visible for this reason.

A horizontal oscillation is imparted to the feed carrier 32 by an exchangeable eccentric disk 41 fitted on the front end of the drive shaft 12, locked against rotation relatively to the shaft 12 by a key 42, and held in place by a nut 43.

The eccentric disk 41 is engaged by a connecting piece or follower 44 operating in the nature of a connecting rod. The follower is pivotally mounted to the feed carrier by means of a stud 45 and a bushing 46 fitting over the stud and inside of bore 47 of the follower. A nut 48 (Figure 2) holds the bushing 46 and follower 44 in place.

As the drive shaft 12 revolves, the eccentric disk 41 moves with it and causes the stud 45 to move to the left and to the right, thereby imparting a horizontal motion component to the feed carrier 32 and to the lower feed gripper 31. It is readily seen that the length of the horizontal stroke is a function of theeccentricity of thev disk 41. For this reason the length of the feed stroke or,

Figure 6 shows the needle in its'upper-' in other words, the number of stitches per inch, may be varied by exchanging a disk of a certain eccentricity for a disk of different eccentricity. The disks are commonly marked by a number indicating the number of stitches per inch.

It is thus seen that a complex oscillatory motion is imparted to the feed carrier 32 and to the lower feed gripper 31 by a vertical oscillation of a magnitude determined by the eccentricity of the shaft portion 40 and, superimposed thereon, a horizontal oscillation determined by the eccentricity of the disk 41.

The lower feed gripper 31 has two rows of teeth 49 and 50 (Figure 6) protruding through apertures 51 and 52 in the needle plate 21 which also has a screw hole 53 for securing the plate to a post 54 at 55 (Figure 4).

A presser foot 56 (Figures 4 and 6) is mounted on an arm 57 having a forked end 58 with a vertical hole of a plunger 63. The plunger is best seen in Figure 4 and is 'slidable in a direction somewhat slanted to the vertical in a plunger housing 64. Details of the plunger construction may follow conventional design. Suflice to say that the plunger 63 is under the action of a spring inside the plunger housing, but not visible in the figures. The spring may be compressed by a knurled adjustment screw 65 of conventional design.

An arm 66 pivoted at 67 and normally pulled upward by a spring 68' engages the angle piece 61 at 69. The engagement is such that, upon depression of the lever 66, the angle piece is tilted in a counterclockwise direction, thereby raising the presser foot 56 against the action of its spring in the housing 64. The arm 66 is usually operated by a chain or cable leading to a foot pedal in front of the machine operator.

Up to this point the description has dealt with conventional and known structural details of the machine and will now turn'to the improvements provided by the invention Referring to Figures 1, 2, 3 and 6, an upper feed gripper70 is arranged opposite the lower feed gripper 31 and above the needle plate 21. The upper feed gripper 70 is pivotally mounted on a double armed lever 71 at 72. The pivot 72 is near one end of the lever 71 and a stud 73 is mounted on the lever near its other end. This stud rests ina forked bearing 74 of an extension 75 secured to the feed carrier 32 by an Allen screw or bolt 76. The bearing .74 therefore moves with, and reproduces the motion of, the feed carrier 32actuating the lower feed gripper 31.

The doublearrned lever 71 whose stud 73 rests in the forked bearing ,74 has an intermediate bearing point or guideway,'sho,wn in the illustratedembodiment as having I the form of an elongated aperture 77, engaged by a pin 78 on a further plunger 79 in an. outer housing 80 fitting over the plunger housing. The plunger 79 is under the action'of a spring 81 indicated in broken lines in Figure} and the tension of the spring is adjustable by an adjustment screw 82. V

The elongated shape of the aperture 77 permits the lever to execute in limited motion in a horizontal direction, as it must, in order to follow the motion of the feed carrier 32which has a horizontal motion component. It is also readily seen that the double armed lever 71 inverts'the vertical component of the motion of the feed carrier. 32 and transmits the inverted vertical motion to theupper feed gripper 70.

If, therefore, the lower feed gripper moves in an upin a direction away from the operator asa result of the horizontal motion component created by the cam disk 41. At thev end of the feed stroke the lower feed gripper 31 is retracted below the needle plate 21 as a result'of the downward motion of the feed carrier 32. The extension 75 of the feed carrier and the stud 73 likewise move in a downward direction causing the'lever 71 to. tilt so that the upper. feed gripper 70 is. liftedfrom the material..

At this phase of the operation the material should be held againstsliding. This is accomplishedby the presser foot which bears down on the material by spring pressure. It is readily seen that it would be undesirable to maintainpressure by the presser foot during the feeding phase of the operation. For this-purpose the presser foot is periodically lifted from the material by a mechanism which will now be described.

Referring to Figure 6,, the. presser foot 56 has a'lug 83 at its front end. The lug has an aperture 84 therethrough-engaged by a link 85 shown in disassembled condition in Figure 6 and shown assembled in Figures l to 4. The link extends to a lever 86 pivotally mounted to the machine housing; at 87. A push rod 88 is secured to the knife carrying arm 26 at 89'and therefore moves up and down in the rhythm of the feed motion. During its upward motion the push rod strikes the underside of the lever 86 and moves the lever in an upward direction, thereby lifting the presser foot through the link 85.

Figure 1 shows the machine in the position in which both feed grippers 31 and 70 are in engaging position. At this phase the push rod 88 is near its uppermost position and the presser foot 56 is raised. In Figure 2 the lower feed gripper 31 is shown retracted while the upper feed gripper 70 only bears lightly upon the needle plate 21. At this phase of the operation the push rod 88 and the lever 86 are disengaged.

The link 85 may be provided with a knurled adjustment screw 90 for adjustment of the stroke imparted to the presser foot56.

A conventional machine equipped with only a lower feed gripper may readily be converted into a machine having an upper as' well as a lower feed gripper by an attachment comprising, basically, an outer plunger hous ing 80 fitting over the plunger housing 64 and secured thereto by means of the same two screws 91 which hold the cover plate 92 of the original plunger housing in place.

There is further required an extension 75 for the feed carrier, and upper presser foot 70, with its double arm lever 71. The assembly may be supplemented by the lever and push-up mechanism 86 and 88 for actuating the presser foot 56.

What is claimed is:

1. An intermittent feeding mechanism for a sewing machine, the mechanism comprising, a base; a drive shaft rotatably mounted on said base; a feed carrier; a first means on said drive shaft for imparting to said feed carrier an oscillatory motion of a predetermined vertical amplitude; a second means on said drive shaft for imparting to said feed carrier an oscillatory motion of a predetermined horizontal amplitude; alower feed gripper on said carrier; a double armed lever; a pivot engaging said lever intermediate its ends to provide freedom of horizontal movementof the lever relatively to said pivot andfreedom of pivotalmovement of: the lever about said pivot; means for supporting said pivot on said base for movement in a substantially vertical direction relatively to said base; spring means reacting on said base for urg- 6 ing said pivot in a downward sense; an upper feed gripper mountedmmonearmof s'aidvlever "substantially opposite said. lower feed gripper; and ;a-pivotal, bearing on said feed carrier engagingqtherother arm of said lever.-

2; An intermittent feeding. mechanism for sewing machines, the 'mechanism comprising, an aperturedneedle plate; apresser footabove said needle plate; spring meansforur'ging said presser foot toward said needle, plate; a drive shaft; a feed carrier, having two oppositely and horizontally extending guidewaysg :a first eccentric onsaid drive shaft; a first follower onxsaid first eccentric, said first follower beingxslidably movable in one of said carrier guideways; a second-eccentric onsaid drive shaft; a, second follower on saidysecond eccentric, said second follower being; pivotallymounted on said carrier about a pivot axissubstantially parallel to, and horizontally spaced from, the drive shaftaxis; a-fixed pivot; a cross head pivotally, mounted on said fixed, pivot, said cross head engaging the other guideway: of the carrier; alower gripper on said carrier, said lower, gripper extending through said needle platega double-armed lever; a pivot engaging said leverintermediate its ends to provide freedom of horizontal movement of'the lever: relatively to said pivot and freedom of pivotalmovement ofthe lever about said pivot; means for supportingsaid pivot for movement in a substantially" vertical direction; spring means for urging said pivot in a. downward sense; an upper feed gripper mountedon one arm of said lever substantially opposite saidl'ower-feed gripperrandadjacent said presser foot; and a, pivotal bearing on said feed carrier engaging the other arm of said lever.

3. An'intermittent feeding mechanism for sewing machines, thernecha'nism comprising, a driveshaft; a feed carrier; a first eccentric on said'drive shaft for imparting a vertical oscillation'tosaid carrier;tbearing means for supporting said carrier for pivotal movement about, and horizontally slidable movement relatively to, said bearingmeans, saidbearing means being horizontally spaced from said first eccentricya second eccentric on said drive shaft; a follower on: said carrier, said follower being engaged by said second eccentric for imparting'a horizontal oscillation of predetermined amplitude to said carrier; a lower feed gripper on said carrier; an apertured needle plate above said lower feed gripper; an upper feed gripper above said needle plate and substantially opposite said lower-feed.- gripper; and actuating means for said upper feed gripper, said actuating means including a double armed lever; one arm of said lever being connected to said: carrier for movement thereby, the other arm of said lever supporting said upper. gripper, a lever pivot supporting said lever forpivotal movement about, and substantially horizontal slidable movement relatively to, said lever pivonand a spring urged element in said actuating means for urging said upper gripper towards said needle plate.

j 4. An intermittent feeding mechanism for sewing machines, the mechanism comprising, a drive shaft; a feed carrier; a first eccentric onsaid drive shaft for imparting a vertical oscillation tosaid carrier; bearing means for supporting said carrier for pivotal movement about, and horizontally slidable movement relatively to, said heating. means, said bearing means being horizontally spaced from said first eccentric; a secondeccentric on said drive shaft; a follower on said carrier, said follower being engaged by said second eccentric for imparting a horizontal oscillation of predetermined amplitude to said carrier; a lower feed gripper on said carrier; an apertured needle plate above said lower feed gripper; an upper feed gripper above said needle plate and substantially opposite said lower feed gripper; actuating means for said upper feed gripper, said actuating means including a double armed lever, one arm of said lever being connected to said carrier for movement therewith, the other arm of said lever supporting said upper gripper, a lever pivot supporting said lever for pivotal movement about, and substantially horizontal slidable movement relative to said lever pivot, and a spring urged element in said actuating means for urging said upper grippertowards said needle plate; a presser foot above said needle plate adjacent said upper gripper; a spring for urging said presser foot towards said needle plate; and means timed with respect to said drive shaft for periodically lifting said resser foot from said needle plate against the action of said spring.

5. An attachment for converting a single gripper sewing machine into a double gripper machine, the machine being of the type comprising an apertured needle plate; a lower'grip'per'extending through the needle plate; a feed carrier below the needle plate upon which carrier the lower gripper is mounted; means for imparting to said carrier a compound oscillatory motion of a predetermined vertical and a predetermined horizontal amplitude; a.

presser foot opposite the lower gripper; an upright plunger supporting the presser foot; and a plunger housing through which said plunger extends, the conversion attachment comprising, an upper feed carrier extension to be secured to said carrier; an outer housing to be fitted over said plunger housing; a second plunger slidable in said outerhousing; a spring for urging said second plunger in a downward sense; a pivot on the second plunger; a double armed lever mounted on said pivot intermediate the ends of the lever with freedom to pivot about, and slide substantially horizontally with respect to, said pivot; means for pivotally connecting one arm of said lever to said extension; and an upper feed gripper mounted on the other arm of said lever.

6. An attachment for converting a single gripper sewing machine into a double gripper machine, the machine being of me type comprising an apertured needle plate; a lower gripper extending through the needle plate; a feed carrier below the needle plate upon which carrier the lower gripper is mounted; means for imparting to said carrier a compound oscillatory motion of a predetermined vertical and a predetermined horizontal amplitude; a presser foot opposite the lower gripper; an upright plunger supporting the presser foot; and a plunger housing through which said plunger extends, the conversion attachment comprising, an upper feed carrier extension to be secured to said carrier; an outer housing to be fitted over said plunger housing; a second plunger slidable in said outer housing; a spring for urging said secondplunger in a downward sense; a pivot on the second plunger; a double armed lever mounted on said pivot intermediate the ends of the lever with freedom to pivot about, and slide substantially horizontally with respect to, said pivot; means for pivotally connecting one arm of said lever to said extension; an upper feed gripper mounted on the other arm of said lever; a pivotal arm; a link between said arm and said presser foot; and a push bar adapted to be attached to a vertically oscillating element for periodically lifting said arm. 7

7. An intermittent feeding mechanism for a sewing machine, the mechanism comprising, a base; a drive shaft rotatably mounted on said base; a feed carrier; a carrier bearing on said base for supporting one end of said feed carrier for pivotal and substantially horizontal translatory motion relatively to said base; a lower feed gripper at ti e other end of said feed carrier; a first means operated by said drive shaft for imparting to said feed carrier an oscillatory motion of a predetermined vertical amplitude; a second means operated by said drive shaft for imparting to said feed carrier an oscillatory motion of a predetermined horizontal amplitude; a double armed lever; an upper feed gripper at one end of said double armed lever substantially opposite said lower feed gripper; an intermediate bearing on said feed carrier intermediate the ends of the feed carrier, said intermediate bearing being horizontally spaced from said carrier bearing, so as to take part of both the vertical and the horizontal oscillatory motion of the feed carrier, said intermediate bearing supporting the other end of said double armed lever, remote from the upper feed gripper; and a rocker bearing on said base for engaging said lever intermediate its ends for rocking and substantially horizontal slidable movement relatively to said base. V

8. An intermittent feeding mechanism for a sewing machine, the mechanism comprising, a base; a drive shaft rotatably mounted on said base; a feed carrier; a carrier bearing on said base for supporting one end of said feed carrier for pivotal and substantially horizontal translatory motion relatively to said base; a lower feed gripper at the other end'of said feed carrier; a first eccentric on said drive shafttfor imparting a Vertical oscillation to said other end of said feed carrier; a second eccentric on said drive shaft; a follower on said carrier, said follower being engaged by said second eccentric for imparting a horizontal oscillation of a predetermined amplitude to said feed carrier; a double armed lever; an upper feed gripper at one end of said double armed leversubstantially opposite said lower feed gripper; an intermediate bearing on said feed carrier intermediate the ends of the feed carrier, said intermediate'bearing being horizontally spaced from said carrier bearing, so as to take part of both the vertical and the horizontal oscillatory motion of the feed carrier, said intermediate bearing supporting the other end of said double armed lever, remote from the upper feed gripper; a rocker bearing for engaging said lever intermediate its ends for rocking and substantially horizontal slidable movement relatively to said rocker bearing; means for mounting said rocker bearing on said base with freedom of vertical movement; and spring means on said base for urging said rocker bearing in a downward direction toward said lower feed gripper.

9. An intermittent feeding mechanism for a' sewing machine, the mechanism comprising, a base; a drive shaft rotatably mounted on said base; a feed carrier; a carrier bearing on said base for supporting one end ofsaid feed carrier for pivotal and substantially horizontal translatory motion relatively to said base; a lower feed gripper at the other end of said feed carrier; a first means operated by said drive shaft for imparting to said feed carrier an oscillatory motion of a predetermined vertical amplitude; a second means operated by said drive shaft for imparting to said feed carrier an oscillatory motion of a predetermined horizontal amplitude; a double armed lever; an upper feed gripper at one endof said double armed lever substantially opposite said lower feed gripper; an intermediate bearing on said feed carrier intermediate the ends of the feed carrier, said intermediate bearing being horizontally spaced from said carrier bearing, so as to take part of both the vertical and the horizontal oscillatory motion of the feed carrier, said intermediate bearing supporting the other end of said double armed lever, remote from the upper feed gripper; and a rocker bearing on said base for engaging said lever intermediate its ends for rocking and substantially horizontal slidable movement relatively to said base; a pressure foot adjacent the upper feed gripper; spring means for urging the pressure foot towards said lower feed gripper; and means timed with respect to said drive shaft for periodically lifting said pressure foot against the action of said spring means.

References Cited in the file of this patent UNITED STATESPATENTS 204,704 Beukler June 11, 1878 591,517 Woodward Oct. '12, 1897 2,341,448 Knaus Feb. 8, 1944 

